Phenotypic variation and biomass partitioning during post-flowering in two common bean cultivars (Phaseolus vulgaris L.) under water restriction

Abstract

Common bean (Phaseolus vulgaris L.) is a major source of dietary protein and minerals in Latin America and Africa. Drought causes severe losses in the yields of many common bean cultivars. In this study, to obtain phenotypic variation over time on common bean under water restriction, we used a phenotyping platform with a sensor for visible (RGB). We hypothesized that greenness identification or “stay green” by high-throughput images is an efficient indicator for identifying differences among the common bean phenotypes. Plants of cultivars V8025 and Canario-60 under greenhouse conditions were irrigated to field capacity until the beginning of the seed-filling stage. Under well-watered conditions, whole plant senescence differed between the cultivars. V8025 seemed to maintain a constant green color throughout the evaluation, whereas the Canario-60 began to show yellowing at 24 d into the evaluation. Images showed early strong symptoms of senescence in the V8025 plants under water restriction; even significant necrosis was observed. In contrast, Canario-60 showed fewer symptoms of senescence than V8025 for half of the evaluations. Although both cultivars showed low yield under water restriction, the Canario-60 seed weight increased significantly. We suggest a non-invasive framework for using an image-based phenotyping platform for common bean screening under stress conditions.